This invention is broadly applicable to the art of dispensing, especially to dispensing flowable products or fluids of all types, specifically to dispensing liquids, and still more specifically to dispensing beverages. In its most specific application, the invention provides an apparatus and method for dispensing beer from a bulk container, such as a keg or a large bottle. In the art of bulk dispensing, a problem originates in the conflicting needs to maintain freshness and to dispense a variety of flowable products. Dispensing the product with a somewhat constant rate of flow requires that the pressure within the bulk container be supplemented as the product volume decreases due to use. In some containers, this need is met by providing a means for supplying additional gas, such as air, carbon dioxide or nitrogen into the container as required. While certain gases may be inert or at least do not degenerate the quality of the product, it is overly expensive and difficult to supply such a suitable gas with each bulk container of product, especially for home use. Further, placing substantially any gas over the product is likely to lead to changes that may be undesirable. Thus, in the beer dispensing art, the practice in the art has been to supply a pump, so that the bulk container can be repressurized as needed, employing ambient air as the propellant gas. In some instances, however, the practice has been to supply a cylinder of pressurized carbon dioxide. Both practices lead to certain disadvantages.
In the dispensing art, persistent problems relate to the interaction between the fluid and the propellant gas. For example, when the fluid is beer and the propellant gas is air or otherwise contains oxygen, the beer begins to oxidize and lose freshness, flavor and quality upon exposure to the propellant gas. Further, if common gases such as oxygen, nitrogen, or carbon dioxide are used, the carbonation level of the beverage is altered. Specifically, placing oxygen or nitrogen over the beverage alters the partial pressure of the carbon dioxide dissolved in the beverage, resulting in a loss of carbonation in the beverage. On the other hand, if carbon dioxide is employed as the propellant gas, the partial pressure of carbon dioxide increases, correspondingly increasing the carbonation of the beverage. In either situation the result is undesirable, since the nature of the beverage is altered.
The art contains at least one successful apparatus for pressurizing a bulk container for flowable product while separating the product from the propellant gas or pressure generator. This art is found in U.S. Pat. No. 4,923,095 to Dorfman et al. According to the teachings of the Dorfman patent, a sealed, expandable pouch or bladder contains a two-component gas generating system, such as citric acid and bicarbonate of soda. Initially, the two components are physically isolated so that they do not generate gas. The pouch can be inserted into a beverage container, such as a keg or large bottle, and the container then can be filled with beverage and sealed. At some point in time, either shortly before inserting the pouch or at a later time, the two components of the gas generating system must be placed in mutual contact so as to generate gas to expand the pouch and thereby pressurize the container to dispense the beverage. The pouch contains a plurality of sub-compartments so that it can expand in stages. As the beverage volume progressively decreases, pressure within the pouch progressively opens new sub-compartments. Each sub-compartment contains a component of the gas generating system, with the result that as each sub-compartment is opened, more gas can be generated.
The technology of the Dorfman patent effectively solves the problems of chemical interaction of the beverage and the propellant. However, it creates new and unsolved problems. Specifically, the problems are when and how to trigger or initiate intermixing of the two components of the gas generating system. If the components are mixed before the pouch is inserted in the keg, the pouch might expand too soon and be unusable. If the components are to be mixed after the pouch is inserted, inflation still might be too fast to allow filling the container with the beverage and sealing it. Causing the components to mix after the pouch is inserted, or after the container is filled with beverage, or after the container is sealed, is difficult and leads to unreliable performance.
The Dorfman patent proposes various ways that the gas system can be actuated within a suitable time frame. Notably, in a production line container filling situation, reliability must be very high since reworking already-filled containers is expensive in wasted time, wasted containers, wasted pouches, and wasted beverage. Dorfman proposes a slow-acting, time delayed, initial gas generating system in which two components of the system initially are isolated in adjacent sub-compartments. The system is activated by striking or otherwise applying pressure to the pouch to open and interconnect the two sub-compartments before it is inserted in the container. When the applied pressure has opened the sub-compartments and caused the two components of a gas generating system to mix, these components begin a slow generation of gas. No time-delayed system has proven to be fully satisfactory, since there are many possibilities for unreliable performance or malfunction. For example, the process of filling and sealing containers can involve unscheduled time delays of unpredictable length, so any pre-triggered activation of the gas system can lead to wasted materials.
Several proposed triggering techniques attempt to actuate the gas system after the container is filled and sealed. One method is to use a first open-ended sub-compartment that contains and isolates one component of the two component gas system in the pouch. This sub-compartment communicates at its open end with a second sub-compartment of the pouch, and this second sub-compartment contains the second component of the gas generating system. With this system, the open end of the various sub-compartments must be kept upright until the pouch has been inserted in the bulk container and the container has been filled. Thereafter, inverting the container, and hence the pouch, mixes the isolated first component with the second component and thereby actuates the gas system. However, this system is not satisfactory, since the pouches are likely to be inverted at any time by accident or while being handled and shipped. This triggering method also presents a problem because, in practice, the pouch must be folded before being inserted into the bulk container. Folding and inserting the pouch tends to squeeze and deform the sub-compartments, prematurely discharging the isolated chemicals from the sub-compartments, thereby prematurely initiating the gas generating system.
In the case of carbonated beverages, another proposal is that the beverage itself can actuate the gas generating system by use of its own carbonation. According to this method, a sealed container of actuating chemical, i.e., citric acid, is located inside the pouch. A barb is located inside the container near a flexible sealing membrane. This technique proposes that the pressure of the carbonated beverage eventually will flex the membrane against the barb, cutting the membrane and releasing the isolated chemical to initiate the gas generating reaction. This technique is not satisfactory, as it can be both costly and unreliable. It also offers the added danger that the barb will puncture the pouch itself, releasing the gas system chemicals into the beverage. Further, the carbonated beverage must become relatively warm to be able to generate enough pressure to activate such a trigger. In addition, in this method it is a very slow process to depend upon the carbonated beverage to generate enough pressure through warming. Thus, the method is unreliable and not suitable for a relatively high speed filling operation. Finally, this method is totally unsuitable for use with any non-carbonated fluid.
It would be desirable to develop a triggering technique that is highly reliable, repeatable and reproducible so that the components of a gas generating system can be actuated shortly after the pressure pouch is placed in the beverage container and the container has been filled and sealed.
Similarly, it would be desirable to have a pressure pouch that can be handled freely and pre-folded for ready insertion and deployment in the product container. This is possible, however, only if such handling will not actuate the gas generating system.
Also, it would be desirable to have a pressure pouch that can be pre-sterilized. With the triggering device shown in the Dorfman patent, other than the barbed trigger, pre-sterilization and pre-folding of the pouch are very difficult, since the trigger must be accessible immediately prior to insertion in the container or the pouch must be held upright until placed upright in the container. For example, if the pouch must be unfolded and struck to initiate gas generation, such handling and striking defeats the sterilization.
Most importantly, it would be desirable to have a pressure pouch that lends itself to high speed filling of the product container.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the pressure activated trigger for a pressure pouch and method of operation of this invention may comprise the following.